The rapid emergence of the membrane bioreactor (MBR) has lead to the deployment of several types of membrane devices in such MBR's, in both “submerged membrane” and pumped “external loop” membrane module configurations. For the submerged membrane configuration, which is favored due to lower costs, there are primarily two membrane types employed: polymeric hollow fibers and polymeric plate devices. Descriptions of the state of the art for both submerged and external loop technology can be found in the following:                1. Articles in the June 2002 issue of Filtration+Separation, Vol. 39, no. 5, pages 26-35.        2. Proceedings of the Microfiltration III Conference, Costa Mesa, Calif., May 5-7, 2002.        3. “Membrane Bioreactors: Wastewater Treatment Applications to Achieve High Quality Effluent”, by Steven Till and Henry Mallia, presented at the 64th Annual Water Industry Engineers and Operators' Conference, Sep. 5-6, 2001, Bendigo, Australia.        
The last paper describes the two leading submerged systems, hollow fibers sold by Zenon (Canada) and plate devices sold by Kubota (Japan). The invention that is the subject of this patent application and that can be used in a submerged MBR is a substantially different membrane configuration, viz. a multiple passageway monolith membrane device. The structures covered by this invention have the characteristics of intrinsically low cost and a very high membrane surface area per unit volume of the device.
Similar devices in various structures when used as crossflow membrane modules, as could be used in external loop MBR's, have been disclosed in the following patents, specifically incorporated herein by reference:                1. U.S. Pat. No. 4,781,831 (Goldsmith), which discloses in FIG. 5 therein, and described in the patent Specification, a cluster of individual multiple passageway monoliths arranged to have “filtrate flow conduits” formed by the space among the monolith elements.        2. U.S. Pat. Nos. 5,009,781 and 5,108,601 (Goldsmith), which therein disclose in the Figures and Specification unitary monolith structures with filtrate conduits formed within the monoliths.        3. U.S. Pat. No. 6,126,833 (Stobbe, et al.), which discloses structures comprised of a collection of monolith segments containing both segment internal filtrate conduits and a filtrate conduit arrangement formed by the gap among the monolith segments.        
Preferred embodiments of the monolith based membrane device would be fabricated from a porous ceramic monolith support and a finer-pored ceramic or polymeric membrane coating applied to the passageway wall surfaces of the monolith support.
Ceramic membrane microfiltration (MF) and ultrafiltration (UF) devices have been used in external MBR systems. Examples are found in an article by Wen, Xing, and Qian (“Ceramic Ultra Filtration Membrane Bioreactor for Domestic Wastewater Treatment”, Tsinghau Science and Technology, ISSN 1007-0214, 08/17, Vol. 5, No. 3, pp 283-287 (September 2000)) and an article by Fan, Urbain, Qian, and Manem (“Ultrafiltration of Activated Sludge with Ceramic Membranes in a Cross-Flow Membrane Bioreactor Process”, Water Science & Technology, Vol. 41, No. 10-11, pp 243-250 (2000)).
There has been little work using ceramic membranes in a submerged MBR configuration. A recent presentation by Xu, Xing, and Xu entitled “Design and Application of Airlift Membrane-Bioreactor for Municipal Wastewater Reclamation” describes the use of an airlift MBR using single tubular ceramic UF membrane elements and a five (5) channel multichannel UF membrane element (Presentation at the North American Membrane Society Meeting, May 11-15, 2002, Long Beach, Calif.).